Mundus

Mundus (lit. "World" in Latin) is the primary antagonist of the first Devil May Cry, and his defeat at the hands of Sparda two millennia ago sets the scene for the series. He is the ruler of the Underworld and was once Sparda's arch-rival.

Before Devil May Cry 3
Two millennia ago, the Devil Prince Mundus was born into the depths of the Demon World as it snowed in the Human World, and quickly rose to power. He planned to lead an assault on the Human World, as he wished to conquer it and rule both realms, but Sparda, one of his chief generals, awoke to justice, leading him to single-handedly defeat both Mundus and his armies, and seal the main gate within the Underworld. In response, Mundus planned revenge against Sparda's family. His demons attacked and killed Eva, Sparda's wife and Dante and Vergil's mother.

Devil May Cry 3
At the end of Devil May Cry 3, as Sparda's son Vergil found himself trapped in the Demon World, he comes upon Mundus and challenges him in battle. However in his weakened state, he is defeated, and transformed into Nelo Angelo, leading into the events of Devil May Cry.

Devil May Cry
In Devil May Cry, Mundus attempts to escape into the Human World by opening a gate on Mallet Island. At the same time, he uses Trish to manipulate Sparda's other son, Dante, into coming to the island so that he can be killed. Though Dante does come to the island, he is able to defeat Mundus and his minions, and Mundus falls back into the Demon World. Mundus appears to have been worshipped as a god by the residents of Mallet Island, as Dante comes across many clues of strange rituals during the game. Before leaving the human world, the beaten Mundus promised to return one day and rule the world.

Physical Appearance
When Dante arrives on Mallet island, Mundus is first seen in his dormant form: a marble statue of a three-eyed, angelic youth with long hair. The statue is located in the hall of the castle, however, Dante does not recognize it as the Demon Emperor, referring to it simply as "a statue of a god that castellans worshipped". Later, the statue disappeared from the main hall, as Mundus moved to his lair in Underworld. When Dante finally encounters Mundus, he is able to attack him using powerful magic while still being in this dormant form. He then transforms into his real form to battle Dante.

Mundus's appearance when he battles Dante is that of a gigantic living statue of an old, bearded angel with a big hole in the chest, where an eye-like core is located. During his final battle with Dante, the statue breaks away, revealing a grotesque, writhing mass of living tissue, with three eyeballs and hundreds of hands coming out of it.

Also, Mundus often appears as three glowing orbs (eyes) arcing with energy. He is seen this way while communicating with Griffon, Trish, and before battling Vergil.

Background
The Mundus Cereris was a pit in Roman mythology which contained an entrance to Hades, the underworld, which was ruled by Pluto, the Roman god of the underworld; Mundus is identified as Pluto twice within Devil May Cry. The stone covering the pit, known as the lapis manalis, would be removed three times a year, and when it was removed it was believed that the spirits of the blessed dead would commune with the living.

Mundus's three eyes are likely a reference to Satan, who is portrayed with three faces in Dante Alighieri's The Divine Comedy. Satan is also considered the "Prince of This World" and the "Prince of Darkness", both of which are titles that Mundus shares with him. Mundus's pseudo-angelic appearance also coincides with Satan's role as a fallen angel within the Christian Faith.

Trivia

 * In the opening cutscene of Devil May Cry 2, a nearly exact copy of the statue of Mundus (his younger, angelic form) is briefly shown as the narration recounts a portion of the tale of Sparda.
 * During the fight with Berial, a sign reading the name "Mundus Vivendi" (Latin for "Mundus Lives") can be seen briefly twice, once before falling from it's post, and again when it is shown on the ground.
 * Mundus is mentioned by Ghost Rider in Ultimate Marvel vs. Capcom 3. Before the battle between Trish, he will say "I eat demons like Mundus for breakfast.". Also, Phoenix (Jean Grey) after defeating Vergil will say "Perhaps if I'm not too busy, I'll take care of Mundus, too."